Do logs persist after reboot? Or they start loggin on each boot? Because then I don't see anything that caused the crash
kodi.log contains info about your current session. If LE crashes and reboots, kodi.old.log contains the crash.
Because pastekodi only works for kodi.log, I suggest to upload kodi.old.log to PasteBin, and post the link.
I only use SSH login and nano editor to read / write / create files. 
titoasi Remove all banned add-ons and repos. If the problem remains after this, post another log.
I would disconnect the fan for testing, and see whether you still need the workaround to avoid a reboot. If no workaround is needed after this, then something is fishy with the fan.
There is a chance that you've connected your fan wrongly, and that has caused your reboot issue. The fan eventually generates some voltage on a pin, which triggers a reboot.
So whatever fan you have, RTFM, and connect it wisely.
dumpkeys is missing on libreelec i guess, from quick googling did not find way to add it , any help would be appreciated.
I can only guess that dumpkeys is needed by the script to create a keymap.
You have to read, what dumpkeys (click the link) does, and find a workaround.
Our Wiki has instructions, how to create a keymap manually. Maybe that's your workaround for dumpkeys.
You still haven't described your used hardware and LE version, so I'm not wondering that little help is coming in.
Is there a way to check/ log what happens?
CEC setting: switch to "ignore", if TV is switched of -- devs might consider to set this behaviour as default, as faulty CEC behaviour seems to be quite common
I also use this setting. I don't think default settings will change because of that issue. Default means perfect world. 
If your fan has an on / off mode (only two contacts in use), then you can apply the same wiring and software, like for the status LED. Switch it on by the auto-start script, and after shutdown the pin goes (hopefully, in your case) back to default state, which means off for the fan.
Good to hear. In my link at post #2 I gave instructions, how to power on / off a status LED. That's usable for your fan problem, too.
Use the default skin. It might be a wrong function mapping on a custom skin.
Disable the CEC adapter on the input settings (click on it, and deactivate it). I think RPi gets a CEC wake-up call after shutdown.
If you need CEC, only deactivate CEC wake-up functions on those settings.
If that doesn't help, provide a proper kodi.old.log, like I said above.
Thanks for the verification. Do you have a spare microSD? If yes, install LE 10.0.4 from scratch on it, and try again.
If no success with those factory defaults:
To be precise, you have two options:
a) SSH login from another PC
b) Use an LE terminal add-on
I tested a 64-bit build of LibreELEC and it does improve VC-1 playback.
Hopefully LibreELEC (Orion) 12 will be 64-bit by default.
That's a big thing! 
How do I get to a command line to run parted?
Login by SSH.
I don't know. Menu shutdown works for me, so I eventually just have different settings.
Please login by SSH, and open /storage/.kodi/userdata/guisettings.xml with the nano editor.
My power management section looks like this. Try the same settings:
<setting id="powermanagement.displaysoff" default="true">0</setting>
<setting id="powermanagement.shutdowntime" default="true">0</setting>
<setting id="powermanagement.shutdownstate" default="true">1</setting>
<setting id="powermanagement.waitfornetwork" default="true">0</setting>
<setting id="powermanagement.wakeonaccess" default="true">false</setting>